1. Field of the Invention
The present invention relates to electronic apparatuses, electronically controlled mechanical timepieces, methods of controlling them, programs for controlling electronic apparatuses, and storage media, and more specifically, it relates to an electronic apparatus comprising a mechanical energy source; a generator which is driven by the mechanical energy source to generate an induced voltage and output an electric energy; and a rotation controlling unit which is driven by the electric energy to control the rotation rate of the generator; an electronically controlled mechanical timepiece, methods of controlling them, a program for controlling an electronic apparatus, and a storage medium.
2. Description of the Related Art
Japanese Patent No. 7-119812 discloses an electronically controlled mechanical timepiece in which mechanical energy released from a mainspring is converted into electric energy by a generator, and a rotation controlling unit is driven by the electric energy to control a current that flows through a coil in the generator, accurately driving hands fixed to a gear train and accurately indicating time.
In this electronically controlled mechanical timepiece, the arrangement is such that a torque (mechanical energy) applied to the generator by the mainspring can rotate the hands faster than a reference speed, and the rotation controlling unit governs the rotation rate by applying a brake. More specifically, the rotation rate of the generator is governed by comparing a rotation detection signal in accordance with the rotation rate of the generator with a reference signal generated in accordance with a signal from a time reference source such as a crystal resonator and setting a brake amount for the generator (e.g., a time for which a brake is applied).
However, when the mainspring is unwound and the spring force of the mainspring is diminished, failing to provide a sufficient rotation torque for the generator, the rotation rate of the generator is diminished, and the operation of hands becomes slow, and the time indication continues becoming slower for a long time.
In this case, the operation of hands is continued although it is slow; thus, there has been a problem that when the user of the timepiece takes a glance at the timepiece to check time, the user erroneously assumes a normal operation even though the time indication is incorrect.
In order to solve the above problem, as is described in Japanese Unexamined Patent Application Publication No. 2000-28757, herein incorporated by reference, the interval at which the rotation detection signal is input is made significantly larger than the interval at which the reference signal is input (reference period). It can then be determined that the rotation rate of the generator has diminished if the value of an up/down counter to which the reference signal and the rotation detection signal are input deviates significantly from a reference value, in which case the generator is halted and the user is thereby assuredly notified of a slower time indication.
For example, a four-bit up/down counter is provided, which counts down when the reference signal is input and counts up when the rotation detection signal is input. The counter applies a brake if the counter value is larger than or equal to xe2x80x9c8xe2x80x9d and releases the brake if the counter value is smaller than or equal to xe2x80x9c7xe2x80x9d. If a large number of reference signals are input before the input of the rotation detection signal, so that the counter value becomes xe2x80x9c2xe2x80x9d or smaller, i.e., if the rotation rate is significantly diminished, a brake is applied to halt the generator.
However, depending on the type of electronically controlled mechanical timepiece, when the rotation rate is significantly diminished, the power generated by the generator is also sometimes diminished, failing to maintain a voltage which is capable of driving rotation controlling means constituted of ICs, etc., thereby causing the rotation controlling means to halt. When the rotation controlling means halts, brake control is not performed. Thus, even though the counter value is xe2x80x9c2xe2x80x9d or smaller, a brake cannot be applied to the generator, raising the possibility that the generator, and therefore the hands, cannot be halted with full assurance.
If the counter value at which the generator is halted is set to a larger value, for example, on the order of xe2x80x9c4xe2x80x9d, the problem that the rotation controlling means halts and a brake control cannot be performed can be avoided. However, it has been found that the counter value can temporarily drop due to a disturbance, for example, and consequently shorten the duration resulting in the generator being halted.
The technique of actively halting the generator in case where a predetermined rotation rate cannot be maintained may be required not only in electronically controlled mechanical timepieces, but also in various electronic apparatuses such as music boxes, metronomes, toys, and electric razors which include portions rotated and controlled by a mechanical energy source such as a mainspring, rubber, etc. when a precise brake control is performed to precisely control operative portions such as a drum in a music box or a pendulum in a metronome, in which case there is also a possibility that the problem described above arises.
It is an object of the present invention to provide an electronic apparatus, an electronically controlled mechanical timepiece, methods of controlling them, a program for controlling an electronic apparatus, and a storage medium, in which the generator is assuredly halted when the rotation of the generator becomes slow, and the generator is not halted due to a temporary effect such as a disturbance, whereby the duration is extended accordingly.
An electronic apparatus in accord with the present invention includes a mechanical energy source; a generator which is driven by the mechanical energy source to generate an induced voltage and supply electric energy; and a rotation controlling unit which is driven by the electric energy to control the rotation rate of the generator; wherein the rotation controlling unit includes brake controlling means that performs a brake control for the generator by comparing a rotation detection signal indicative of the rotation rate of the generator with a reference signal generated in accordance with a signal from a time reference source; and generator halting means that applies a brake to halt the generator if the amount of braking applied to the generator by the brake controlling means in a preset time is smaller than, or equal to, a first braking preset value.
In the present invention, when mechanical energy supplied by the mechanical energy source (i.e. such as a mainspring) is high, the amount of braking applied to the generator in the preset time must be increased in order for the generator to maintain a constant rotation rate.
On the other hand, when the mechanical energy is low (such as when the mainspring being unwound), the amount of braking applied to the generator in the preset time must be decreased.
Thus, when the braking amount in the preset time becomes smaller than or equal to the first braking preset value, it is determined that the energy of the mechanical energy source itself has diminished, and the reduction is not due to a temporary disturbance. Thus, a brake is applied to the generator at that time, so that the duration is prevented from being significantly diminished by incorrectly halting the generator due to a disturbance.
Furthermore, because of the detection of a state in which the amount of braking by the brake controlling means in the rotation controlling unit is smaller than, or equal to, the first braking preset value(i.e., a state in which the brake controlling means is performing a normal brake control is detected), the situation, which has hitherto before been the case, that the rotation controlling unit is halted and a brake cannot be applied to the generator is avoided, and it can thus be assured that the generator can be halted.
The generator halting means preferably includes a braking amount detection means that detects the braking amount by counting the number of brake-off conditions for which a brake-off control is performed so that the brake controlling means does not apply a brake to the generator, and if the number of brake-off conditions in the preset time (as detected by the braking amount detection means) is larger than, or equal to, a preset number of times of brake-off conditions, it is determined that the braking amount in the preset time is smaller than or equal to the first braking preset value, whereby a brake is applied to halt the generator.
According to this invention, as above, the brake control for the generator is performed based on, for example, the phase difference between an 8-Hz reference signal and the rotation detection signal. Thus, for example, if the preset time is one minute, then the brake control is performed at least 8xc3x9760=480 times. The number of brake-off controls among them is then counted. If the number of brake-off controls is larger than or equal to a preset number of times of brake-off conditions (e.g., 64), the ratio of brake-off conditions is larger, so that it is determined that the braking amount is smaller than or equal to the first braking amount preset value, whereby the generator is halted.
At this time, the generator halting means can be readily controlled just by counting the number of brake-off conditions. In addition, just by setting the preset number of times of brake-off conditions as appropriate, the timing at which the generator is halted can be set in accordance with the characteristics of various electronic apparatuses, readily allowing control settings suitable for each of the electronic apparatuses.
The brake controlling means preferably includes an up/down counter to which one of the rotation detection signal or the reference signal is input as an up-count signal and the other is input as a down-count signal. The brake controlling means performs a control function to apply a brake to the generator when the value of the up/down counter becomes larger than a first counter preset value due to the rotation rate of the generator being faster and due to not applying a brake to the generator when the counter value becomes smaller than, or equal to, the first counter preset value. The braking amount detection means counts, as the number of brake-off conditions, the number of times the counter value of the up/down counter is smaller than, or equal to, a second counter preset value, which is smaller than the first counter preset value.
For example, the up/down counter has four bits, and the first counter preset value is xe2x80x9c7xe2x80x9d. The brake-on control is performed when the counter value is larger than, or equal to, xe2x80x9c8xe2x80x9d, and the brake-off control is performed when the counter value is smaller than, or equal to, xe2x80x9c7xe2x80x9d. The second counter preset value is xe2x80x9c6xe2x80x9d, and the number of xe2x80x9c6xe2x80x9d or smaller is counted as the number of brake-off conditions.
According to the arrangement as above, brake-off conditions can be recognized based on the value of the up/down counter, further facilitating the counting of the number of brake-off conditions.
The generator halting means may further include braking amount detection means that detects the braking amount by measuring the time during which a brake-on control is performed. In this way, when the brake controlling means applies a brake to the generator, it is possible to determined if the braking amount in the preset time is smaller than, or equal to, the first braking preset value by counting the number of short-brake applications (defined as application times shorter than a brake-on preset time) and determining if the number of short brake applications in the preset time (as detected by the braking amount detection means) is larger than, or equal to, a preset number of times of short-brake applications. If the braking amount in the preset time is indeed smaller than, or equal to, the first braking preset value, then a brake is applied to halt the generator.
According to this invention as above, the brake control for the generator is executed based on, for example, the phase difference between an 8-Hz reference signal and the rotation detection signal; thus, for example, if the preset time is one minute, then the brake control is performed at least 8xc3x9760=480 times. Each of the brake controls is performed based on the phase difference between the reference signal and the rotation detection signal, so that the time for the brake-on control is automatically adjusted in accordance with the phase difference.
At this time, the cases where the time for the brake-on control is smaller than or equal to the preset time is counted, and if this number is larger than, or equal to, a preset number of times of short brake applications (e.g., 64), then the ratio of short brake-on control is larger and it is determined that the braking amount is smaller than, or equal to, the first braking preset value, whereby the generator is halted.
At this time, the generator halting means is allowed to set two parameters, i.e., a first parameter indicative of the time of the brake-on control for controlling a short brake and a second parameter indicative of the preset number of times of short brake applications. In this manner, the timing at which the generator is halted can be set in accordance with the characteristics of various electronic apparatuses, and thus readily allowing control settings specially selected to suit each of the electronic apparatuses.
The brake controlling means may be capable of applying at least two types of brakes (a strong brake and a weak brake) to the generator. Preferably, the brake controlling means applies the weak brake to the generator when performing a brake-off control, and applies the strong brake to said generator when performing a brake-on control. Furthermore, the generator halting means preferably halts the generator when the brake controlling means applies the strong brake to said generator.
That is, the brake control may be performed by activating and deactivating (zero braking amount) the brake, or by using a large and a small brake.
At this time, in particular, two or more pulse signals having different duty ratios may be applied to switches that can turn ON and OFF both ends of a coil of the generator. In this manner, when a strong brake control is performed to apply a strong brake to the generator, the braking torque of the generator can be increased by applying a pulse signal with a large duty ratio (the switch is ON for a longer time) while suppressing reduction in power generation by means of the pulsing. On the other hand, when a weak brake control is performed to apply a weak brake to the generator, the braking torque of the generator can be minimized by applying a pulse signal with a duty ratio smaller than that of the above pulse signal to the switch (the switch is ON for a shorter time), serving to achieve a sufficient power generation.
Said rotation controlling unit preferably further includes a brake releasing means for releasing the brake that halts the generator. When a brake control operation is initiated to halt the generator, the brake control operation is maintained until the brake is released by the brake releasing means.
By providing the brake releasing means and requiring that the brake control operation be maintained until the brake is released by the brake releasing means, the generator will assuredly be maintained in a halt condition once the brake control operation is started until, for example, the mainspring (which is the mechanical energy source) is wound to return to a state in which a normal rotation is possible.
The brake releasing means preferably releases the brake that halts the generator when a user operates an external operation member, such as a crown, a dedicated button, etc.
By requiring the use of the external operation member to release the brake, it is assured that the brake is released when the user recognizes an abnormal rotation of the generator and operates the external operation member. Thus, the generator is maintained in a halt state by the brake control operation until the user recognizes an abnormality, and thus assuring that the abnormality is recognized.
The brake releasing means may further release the brake that halts the generator after the elapse of a preset time from following the application of the brake.
If the brake is applied for the predetermined time (e.g., on the order of four seconds) when the rotation rate of the generator is diminished, the rotation rate is hardly increased even if the brake is automatically released.
Thus, the user is assuredly notified of an abnormality, and the brake is automatically released, so that when the user reactivates the generator by winding the mainspring(or by some other pre-defined method) after noticing the abnormality, the reactivation goes smoothly and quickly because the brake is released, serving to improve activation characteristics. The predetermined time for which the brake is applied may be set as appropriate with consideration of the mechanical load and the torque of the mechanical energy source (such as the mainspring, etc.). The predetermined time may be set, for example, on the order of two to six seconds.
An electronically controlled mechanical timepiece according to the present invention includes: a mechanical energy source; a generator which is driven by the mechanical energy source to generate an induced voltage and supply electric energy; a rotation controlling unit driven by the electric energy to control the rotation rate of the generator; and a time indication unit that operates in association with the rotation of the generator. Preferably, the rotation controlling unit includes a brake control means and a generator halting means. The brake control means performs brake control on the generator as determined by a comparison of a rotation detection signal indicative of the rotation rate of the generator with a reference signal generated in accordance with a signal from a time reference source. The generator halting means halts the generator and halts the time indication unit if the amount of braking applied to the generator by the brake control means within a predetermined time period is smaller than, or equal to, a first, predetermined braking-amount value.
By applying the above-described electronic apparatus may be implemented as an electronically controlled mechanical timepiece, and when the rotation of the generator becomes slow, the generator is deliberately halted to stop the rotation thereof. In this manner the generator is prevented from operating when it is incapable of generating sufficient power. Furthermore, if a driven portion such as the hands of the timepiece is operatively linked to the generator so that the driven portion is controlled in accordance with the rotation of the generator, it can be assured that hand control is accurately performed without error whenever the generator is in operation. Additionally, and the generator is assuredly halted when the rotation rate of the generator is diminished, whereby the user is unmistakably notified that the timepiece is slow.
The above-described electronic apparatus may be a timekeeping device, a music box, or a metronome. In the timekeeping device, the music box, or the metronome, the generator is prevented from being halted due to a disturbance or other transient event, the rotation thereof is accurately controlled when in operation, and the operation is assuredly halted when the torque of the mechanical energy source is diminished to the point where it fails to maintain an accurate rotation.
When the electronic apparatus is an electronically controlled mechanical timepiece, the above-described external operation member is preferably a crown. More specifically, said rotation controlling unit preferably includes brake releasing means for releasing the brake that halts the generator, and includes brake releasing means releases the brake when a user operates the crown.
In the case of an electronically controlled mechanical timepiece, the hands operate in association with the generator, and when the user recognizes an abnormal operation of hands, the user usually rotates the crown to wind the mainspring. Thus, by making the arrangement such that the brake control for halting the generator (hands) is released when the crown is operated, the user is not required to perform an extra operation for releasing the brake by separately pressing a dedicated button, etc., which serves to improve operability.
A method of controlling an electronic apparatus according to the present invention controls an electronic apparatus that includes a mechanical energy source; a generator driven by the mechanical energy source to generate an induced voltage and supply electric energy; and a rotation controlling unit driven by the electric energy to control the rotation rate of the generator. Determination of when to apply brake control on the generator is made by comparing a rotation detection signal in accordance with the rotation rate of the generator with a reference signal generated in accordance with a signal from a time reference source. The brake is applied to halt the generator if the amount of braking applied to the generator in within a predetermined time period is smaller than or equal to a first braking preset value.
According to this invention as well, when the amount of braking on the generator becomes smaller than or equal to the first braking preset value, i.e., when the rotation rate becomes very slow, a brake is applied to assure that the generator is stopped. Thus, failure to provide a sufficient power generation due to the rotation of the generator being too slow is prevented.
A method of controlling an electronically controlled mechanical timepiece according to the present invention controls an electronically controlled mechanical timepiece that has: a mechanical energy source; a generator driven by the mechanical energy source to generate an induced voltage and supply electric energy; a rotation controlling unit that is driven by the electric energy to control the rotation rate of the generator; and a time indication unit that operates in response to the rotation of said generator. In the present invention, determination of when to apply brake control on the generator is made by comparing a rotation detection signal in accordance with a rotation rate of the generator with a reference signal generated in accordance with a signal from a time reference source, and a brake mechanism is applied to assure that the generator and said time indication unit is halted if the amount of braking applied to said generator by the brake control within a predetermined time period is smaller than or equal to a first braking preset value.
According to this invention as well, when the amount of braking on the generator by the brake control becomes smaller than, or equal to, a first predetermined braking value (i.e. when the rotation rate becomes very slow), the brake is applied to assure that the generator is stopped.
Accordingly, when the rotation of the generator becomes very slow and an error occurs in the time indication unit such as hands operatively associated with the generator, the generator, and therefore the time indication unit, are halted. Thus, an abnormal operation of hands can be recognized when the user takes a glance at the hands, or otherwise checks time, whereby the user is notified that the timepiece is slow. This prevents the user from using the timepiece while leaving the slow timepiece as it is, and prompts the user to perform an operation for winding the mainspring, thereby returning the electronically controlled mechanical timepiece to a normal operation.
A program for controlling an electronic apparatus according to the present invention controls an electronic apparatus having: a mechanical energy source; a generator driven by the mechanical energy source to generate an induced voltage and supply an electric energy; and a rotation controlling unit driven by the electric energy to control the rotation rate of the generator. The program lets the rotation controlling unit function as brake controlling means that applies brake control on the generator as determined by comparing a rotation detection signal in accordance with the rotation rate of the generator with a reference signal generated in accordance with a signal from a time reference source. The electronic apparatus further includes generator halting means applies a brake to halt the generator if the amount of braking applied to the generator by the brake controlling means within a predetermined time period is smaller than, or equal to, a first braking preset value.
A storage medium according to the present invention stores a program for controlling an electronic apparatus having: a mechanical energy source; a generator driven by the mechanical energy source to generate an induced voltage and supply electric energy; and a rotation controlling unit driven by the electric energy to control the rotation rate of the generator. The program lets the rotation controlling unit function as a brake controlling means that applies brake control on the generator as determined by comparing a rotation detection signal in accordance with the rotation rate of the generator with a reference signal generated in accordance with a signal from a time reference source. The electronic apparatus further includes generator halting means applies a brake to halt the generator if the amount of braking applied to the generator by the brake controlling means within a predetermined time period is smaller than, or equal to, a first, predetermined braking value.
By installing on an electronic apparatus the control program according to the present invention via the storage medium or communications means such as the Internet, a brake can be applied to halt the generator when the rotation of the generator becomes slow and the braking amount becomes smaller than, or equal to, the first predetermined braking value, whereby an accurate rotation control is achieved when the generator is in operation.
In addition, because the program can be installed and embedded on an electronic apparatus via a storage medium such as a CD-ROM or communications means such as the Internet, the first braking preset value, i.e. the first predetermined braking value, can be readily and optimally set (or changed) in accordance with the characteristics of various electronic apparatuses, achieving an even more accurate rotation control.